President warns of risks from 'crude' nationalism

US President Barack Obama holds a press conference in Athens on November 15, 2016

US President Barack Obama on Tuesday warned against succumbing to "crude" nationalism in the aftermath of the Brexit referendum and the American vote, and with a wave of European elections looming.

"We are going to have to guard against a rise in a crude sort of nationalism or ethnic identity or tribalism that is built around an 'us' and a 'them'," Obama said in Athens as he embarked on a farewell trip to Europe.

"We know what happens when Europeans start dividing themselves up...the 20th century was a bloodbath," Obama said, adding that the United States was also painfully aware of how "dangerous" it was to "(divide) ourselves along lines of race or religion or ethnicity."